As described in Japanese Patent Application Publication No. 2014-207629, for example, in a case where a plurality of communication devices performs packet communication on a communication network, a plurality of communication modes such as unicast and multicast are employed.
Japanese Patent Application Publication No. 2014-225897, for example, describes a configuration in which a terminal control device and terminal devices perform packet communication wirelessly by way of relay devices (repeater devices) on a communication network. In such a configuration, in updating firmware of a terminal device, the terminal control device transmits data of firmware for update to the terminal device. This data transmission employs a communication mode of any one of unicast, multicast, or broadcast.